Mucociliary transport determined by in vivo microdialysis in the airways of normal and CF mice

1 Cystic Fibrosis/Pulmonary Research and Treatment Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7248; and 2 Department of Surgery/Radiology, School of Veterinary Medicine, University of California-Davis, Davis, California 95616 Submitted 2 September 2003 ; accepted in final form 13 November 2003 We report a novel method to measure mucociliary transport (MCT) in both the upper and lower airways of normal and CF mice. The in vivo microdialysis technique involves placing a small quantity of dye on the airway surface and a microdialysis probe a defined distance from the site of dye deposition. The dye is transported toward the probe by ciliary transport and, upon reaching the microdialysis probe, diffuses across the dialysis membrane and is collected in the dialysate leaving the probe. The rate of MCT is calculated from the length of time from dye deposition to recovery. The rate of tracheal MCT in normal mice was 2.2 ± 0.45 (SE) mm/min ( n = 6), a value similar to that in reports using other techniques. MCT in CF mice was not different (2.3 ± 0.29, n = 6), consistent with previous observations suggesting that tracheal ion transport properties are not different between CF and normal mice. The rate of MCT in the nasal cavity of normal mice was slower than in the trachea (1.3 ± 0.26, n = 4). MCT in the CF mouse nasal cavity (1.4 ± 0.31, n = 8), a region in which the CF mouse exhibits bioelectric properties similar to the human CF patient, was, again, not different from the normal mouse, perhaps reflecting copious gland secretion offsetting Na + and liquid hyperabsorption. In conclusion, we have developed a versatile, simple in vivo method to measure MCT in both upper and lower airways of mice and larger animals. in vivo microdialysis; nasal cavity; trachea; cystic fibrosis Address for reprint requests and other correspondence: B. R. Grubb, Cystic Fibrosis/Pulmonary Research and Treatment Center, The Univ. of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7248 (E-mail: bgrubb{at}med.unc.edu ).